The instant invention relates to the printing of labels, tags and the like and more particularly to a novel apparatus for printing a succession of labels, tags or the like.
The use of preprinted labels is obviously widespread and extends to the marketing of virtually all types of goods. In this regard manufacturers, wholesalers and large retailers frequently have need for large quantities of labels bearing the same imprint; and hence in recent years several machines have been developed for printing such labels in rapid succession. Machines of this type representing the closest prior art of which the applicant is aware are disclosed in the U.S. patent to BURTON, U.S. Pat. No. 3,655,492; SMITH, U.S. Pat. No. 3,662,681; SEIDL et al., U.S. Pat. No. 3,908,544 and SEIDL et al., U.S. Pat. No. 4,027,590. Broadly all of these machines operate by advancing strips of interconnected tags, labels or the like to a printing station where the labels are printed in relatively rapid succession.
The apparatus of the instant invention operates in this same general manner, advancing interconnected labels, tags or the like to a printing station for printing. However, in contrast to the previously known machines of this general type, the apparatus of the instant invention incorporates a mechanically driven print head which always remains substantially parallel to a printing pad at the printing station to provide even printing pressure over the printing surface. Parallel linkage arms which are pivotally connected to the print head and to a substantially vertical support frame operate to cyclically advance the print head to the printing pad to effect printing. The linkage arms which comprise both primary and secondary arms extend generally over the printing pad to position the print head for printing. The primary or driving arms also extend rearwardly from the support frame providing leverage to drive the linkage arms in the print head assembly. Manipulation of the print head assembly is effected through a mechanical drive assembly which operates to cyclically advance the print head toward the printing pad. Substantial leverage provided by the rearwardly extending portions of the primary arms effects desired printing pressures while the head is maintained substantially parallel to the pad through the cooperation of the primary and secondary arms to permit high resolution printing.
While the apparatus herein disclosed is adaptable for various types of printing operations including ink printing and embossed printing, it is particularly suited for thermographic printing operations. In this connection the print head of the apparatus herein disclosed includes a heating element for heating the type elements for thermographic printing. In addition the apparatus includes a thermographic strip feed assembly which operates to stepwisely advance a conventional thermographic foil strip to the printing station during the nonprinting portions of the printing cycles. Accordingly, when the heated type elements are advanced to effect printing, they engage the strip pressing it against a label or tag at the station to effect printing. Although this general type of thermographic printing operation is relatively well known, the label printing machines heretofore available have been generally incapable of consistently effecting high resolution thermographic printing. By incorporating a mechanically driven print head which remains substantially parallel to the printing pad and a parallel linkage arm printing assembly, the apparatus herein disclosed is capable of consistently effecting high resolution printing and therefore represents a significant advancement in thermographic label printers.
The clarity or resolution of a printed image has particular significance in OCR (optical character recognition) labeling systems such as where labels are machine read in computer inventory or pricing systems. In this connection, character widths must be within tolerances of 11 to 14 one thousands of an inch (0.011-0.014 inch) to be read by conventional character recognition equipment or the label will be rejected as unreadable. High rates of label rejection in these systems resulting from poorly printed labels have frequently been the source of substantial accounting errors. Unfortunately, the characters utilized in OCR systems are relatively confusing for operators to read visually. Hence when the poorly printed labels are rejected by the OCR reader, substantial errors are frequently introduced through operator error. The apparatus of the instant invention has consistently proven to be capable of printing OCR quality labels in thermographic printing oeprations, and thereby effectively eliminates this problem.
The drive assembly of the apparatus herein disclosed also has significant advantages over drive assemblies of the previously known machines by effectively assuring optimum coordination between the printing assembly, the label feed assembly and the thermographic strip feed assembly. Operation of the printing assembly is effected through a cam mounted on a drive shaft which is rotated by a drive motor and which communicates through a cam follower frame with the primary linkage arms to advance the print head toward the printing pad. The feed mechanism which operates to stepwisely advance the tags or labels is also driven through mechanical linkage by the same drive motor to provide a direct mechanical relationship between the printing and feeding assemblies. The thermographic strip assembly is similarly mechanically driven by the drive motor to ensure proper timing of strip advancements in relation to print head movement. The printing assembly, the label feed assembly and the strip feed assembly are all independently mechanically adjustable in this regard so that proper timing can always be achieved regardless of label size or other variables.
Accordingly, the primary object of the instant invention is to provide an apparatus for effecting high resolution printing of labels, tags and the like in rapid succession.
Another object of the instant invention is to provide a high resolution thermographic label printing apparatus.
A still further object of the instant invention is to provide a label printing apparatus having a mechanically driven print head which remains substantially parallel to the printing pad throughout the printing operation.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.